Product
Your SKU Isn't Your Supplier's SKU
You keep your SKU. The supplier's code, cost, and case size sit next to it on the same record.
Two names for one product, and only one of them is yours
A SKU is an internal code. You create it for your own catalog and you control it, so two retailers selling the same product will usually give it two different SKUs. Your supplier's warehouse doesn't use your code. It picks from its own item number. Behind that there may be a manufacturer part number, set by the manufacturer in no fixed format, and a GTIN, which the brand owner assigns to identify the item at a given packaging level.
So when you order, someone has to translate. Either you look up their code before the order goes out, or someone at their end works out what you meant by yours. Every translation done by hand risks swapped digits, the wrong size of a product with a similar name, or a guess. The problem isn't that there are two codes. It's that the link between them lives in someone's head or a spreadsheet tab. A cross-reference exists to put that link somewhere permanent.
Four identifiers that can point at the same product
| Identifier | Your SKU | Supplier part number | Manufacturer part number | GTIN |
|---|---|---|---|---|
| Who assigns it | You | The supplier or distributor | The manufacturer | The brand owner |
| Who reads it | Your team and your store | The supplier's warehouse and order desk | Anyone checking the exact make and model | Scanners and trading partners |
| Unique beyond your business? | No, it only means something in your catalog | Only within that supplier's catalog | Only within that manufacturer's range, in no set format | Yes, it identifies the trade item |
| Its job on a purchase order | Tells you what you're buying | Tells the supplier what to pick | Clears up near-identical items | Pins down the item at a packaging level |
What a cross-reference has to hold besides the code
A code mapping alone isn't enough. The same product carries other facts that belong to the supplier relationship, not to the product: what this supplier charges for it, the smallest amount they'll sell, and how many units come in one of their cases. Switch suppliers and all of those can change while your SKU and your listing stay the same.
Case quantity is a common source of quantity mistakes. You count units one at a time. Your supplier may sell by the case. If one side means “12” as twelve units and the other reads it as twelve cases, the order arrives twelve times off. The buying table's suggestions are rounded to your case sizes and capped at your maximum stock levels, so the case figure has to be right before the suggested quantity can be.
Say you list a loose-leaf tea as TEA-EARL-250. Your supplier knows it as NH-4471-C12 and only sells it in cases of 12. On their side, an order line reading “TEA-EARL-250 × 24” means nothing until someone looks up the code. Then they still have to decide whether you want 24 tins or 24 cases. Keep their code and a case quantity of 12 next to your SKU, and the translation is recorded once instead of redone from memory. (Illustrative codes and numbers.)
Storing the supplier's code next to yours
Before a variant can hold its supplier's code, Assisty has to know who supplies it. That usually comes from data you already have. Suppliers are detected from Shopify vendor fields or product metafields, with a preview before anything is created, or imported from a CSV. Products are then auto-assigned by vendor name or by saved rules. The setup itself is covered in what your supplier setup does to the suggestion.
Each supplier then carries its defaults: Lead Time, Reorder Cycle, Min Stock Cover Days, and order minimums and maximums. The buying table's suggested quantities use them automatically. The cross-reference sits one level down. Where one product differs from the rest, you override it per variant: supplier SKU, cost, minimum order quantity, case quantity. Your SKU stays as it is. The supplier's code and terms sit next to it on the same record, so the link is stored rather than remembered.
Assisty Dropship POs, a separate app for stores that hold no stock, applies the same idea. It reads your suppliers from Shopify's vendor field. You add the email you order from, the currency and, where a supplier uses its own code, a Supplier SKU per product. Each paid order then becomes one purchase order per supplier, which you download as a branded PDF, send as you already do, and mark as sent. Entering tracking fulfills the order in Shopify.
The two layers, and where each is set
| Layer | What Assisty holds | Source |
|---|---|---|
| Who supplies it | Suppliers detected from Shopify vendor fields or product metafields with a preview, or imported by CSV; products auto-assigned by vendor name or saved rules | Supplier Management |
| Supplier defaults | Lead Time, Reorder Cycle, Min Stock Cover Days, order minimums and maximums, all used by the buying table's suggestions | Supplier Management |
| Per-variant override | Supplier SKU, cost, minimum order quantity, case quantity | Supplier Management |
| Dropship (separate app) | Order email, currency, and a Supplier SKU per product where a supplier uses its own code | Assisty Dropship POs |
Three events that break a cross-reference
A cross-reference is only useful while it's true, and three ordinary events break it.
The supplier renumbers its catalog. Your SKU doesn't change, but every code you've recorded for that supplier might. Because the supplier SKU lives on the variant's override, that's the one place to update, and nothing about your listing has to move.
You switch suppliers. The new supplier brings its own code, its own price, its own minimum, and maybe its own case size. Assign the product to the new supplier, then set all four on the variant's override. Miss the case quantity and you're back to the twelve-times-off problem, just with a different supplier.
The case pack changes. Say a supplier moves from cases of 12 to cases of 24. It hasn't changed your product, but it has changed what one case means. Because suggestions are rounded to your case sizes, the case quantity on the override is the figure worth keeping current.
New products are the easy part: saved rules link them to their supplier as they're added. When you need to check a supplier's record, the directory searches by name or email and sorts by name, lead time, or product count.
With suppliers and their terms in place, you can create a purchase order from a supplier, or any selection of its products, pre-filled with suggested quantities, the supplier's tax and currency, and a delivery location. From the buying table, a mixed selection splits into one PO per supplier, and a purchase order can be emailed straight to the supplier. The assistant can do the same conversationally: find, create, edit, assign, order.